Amana refrigerators are prone to microcracks in the internal tubing which are impossible to fix. If the freon leak was slow, it probably was from these type cracks. If a fast leak, probably from a bad seal in the evaporator, or an internal compressor leak.
Unfortunately, a low side leak will cause the compressor to suck in non-compressables that will damage the compressor. It may pump up the freon, but it's efficiency will be lower than normal.
A pro would replace both the evaporator and compressor at a cost of well over $ 600. Once fixed, the fridg compressor might fail in the future due to a microcrack which is impossible to see, or repair.